Louis Antoine was their legitimate son and as such was not the son of Louis XIV. He was raised in Gascony with his sister which may have been due to his father's dispute with the King about Madame de Montespan. Nevertheless, he was sent to court in 1683 and was destined for a career in the military where he gained a commission as a lieutenant.
Three years after his arrival at court, Louis Antoine was married to Julie Francoise de Crussol with whom he had two sons. It was through her that he gained access to the inner circle of the Grand Dauphin where he became an established member. Despite his father's well-known and very public dislike of the affair between his wife and Louis XIV - and the children born therefrom - Louis Antoine apparently did not share the dislike. Perhaps he simply saw his royal half-siblings as a golden opportunity but either way he quickly became a fervent supporter of both the Comte de Toulouse and the Duc du Maine.
Sadly, for Louis Antoine not even openly embracing his half-siblings could gain him the affection of the Sun King. For some reason Louis XIV never liked Louis Antoine and the King took the first opportunity to remove Louis Antoine from his military career. This happened in 1707 when Louis Antoine made a grievous miscalculation which resulted in tactical error on the battlefield.
Perhaps his presence had reminded Louis XIV of his mother - who infamously fell from favour - because Louis Antoine only gained favour once she had died. First, he was made governor of Orléanais not long after the death of his mother and then Head of the Bâtiments du Roi - this latter position gave him frequent access to the King who loved building.
He seemed to have become dearer to the King upon closer acquaintance for in 1711 the King bestowed two major favours on Louis Antoine: first he made him Duc d'Antin and then awarded him with the Order of Saint-Esprit. Besides these titles he was also the Marquis de Montespan and Marquis de Gondrin.
Louis Antoine's fondness for building shows in his private life as well. As early as 1692 he purchased the château de Bellegarde and rebuilt it and he inherited the château de Petit-Bourg from his mother where he also effected some changes. Finally, he had a hôtel in Paris which would later become the Hôtel de Richelieu.
When Louis XIV died Louis Antoine did not linger behind in the "old reign" but instead took up a career as a politician during the regency. He even managed to become President of the Council of Matters. Once these councils were abolished he remained on board but in name only. Finally, he left his position in February 1722. This year appears to have been a turning point in Louis Antoine's life and he decided to retire gradually from public life. He even relinquished his title of Duc d'Antin in favour of his grandson (his own son having died in 1712).
Eventually, he lived mainly in his Parisian abode where he died on 2 November 1736.